Thoraxia is a location that appears in the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics. It is a planet in the same galaxy as Mobius, though located many thousands of light-years away. It is home to two sapient, insectoid races: the Blodex and the Bzzzz. It was once home to the red Chaos Emeralds.
The Blodex revered a hero known as Aypex, whose heroism had caused the Blodex to construct a statue in his honor. After Sonic was flung across the galaxy by the destruction of the Quantum Dial, Thoraxia was the first planet he visited. He was found by the natives and implanted with a device that allowed him to communicate with them and other alien species, and even with his dog Muttski when he eventually returned to Mobius. He attempted to defend the Blodex from the Bzzzz by using Thoraxia's red Chaos Emeralds to transform into Super Sonic, but the alien Chaos Emeralds instead created an evil version of Super Sonic who was a separate entity from Sonic. This evil Super Sonic then began to rampage across the planet. Despite being seriously outmatched, Sonic managed to distract the duplicate until it vanished, saving the Thoraxians. Sonic soon left the planet in order to begin his journey home.
- Thoraxia is named after the thorax, one of three main divisions of the body (along with the head and abdomen) in insects. It is the area where the wings and legs attach to the body.